In the field of manufacture of a semiconductor chip or a biochip, optical nanoimprint technology has attracted attention. This is because it is possible to manufacture those chips at low cost by such optical nanoimprinting, compared with a pattern formation method using a conventional photo lithography and etching. For example, Japanese Patent Application Publication No. 2000-194142 discloses such a method.
Although, in such optical nanoimprinting, a template is used to form a pattern on a workpiece to be processed, the template has to be frequently cleaned. This is because, in such nanoimprinting, the template is brought into direct contact with a resist, so that remnants of the resist adhere to the template every time a pattern is formed.
A wet cleaning method using an organic solvent or alkali chemical has been adopted as such a cleaning method of the template. However, in such a wet cleaning method, part of the template dissolves with the organic solvent, chemical, or the like, so that there is a possibility that the pattern shape thereof may change.